This invention relates to a medical device and process and more particularly, to a gradient pressure compression device for removal of excess fluids from body tissue and a method of constructing and using the gradient pressure compression device.
By way of background, the lymphatic system is organized like the blood system and has numerous tiny vessels connected to a network of larger vessels through which a liquid medium containing solutes and particulates is transferred. A healthy lymphatic system continuously drains lymphatic fluid comprising a mixture of lymph, water, proteins and other matter, away from various interstitial areas of the body and back into the blood system. Lymph is the liquid medium or solvent of the lymphatic system.
The lymph fluid is pumped through the lymphatic system and away from various body areas by both the action of adjacent muscle tissue and contraction of the larger lymphatic vessels. Foreign matter is filtered out of the lymph fluid as the fluid passes through bundles of lymph nodes during its passage through the lymphatic system. The lymph nodes also monitor the contents of the lymph fluid to determine if any appropriate immune reactions should be initiated by the host's immune system. The lymph is then transferred back into the blood system after this filtration.
Lymphedema is a deficiency, blocking or dysfunction of the lymphatic system that limits the flow of lymph fluid from a body area. The most frequent causes of lymphedema include primary insufficiency, traumatic accidents, chronic venous diseases, radiation therapy of the lymph nodes, prostate operations, mastectomies, amputations and other surgical operations. Lymphedema most typically occurs in arms and legs, but most other body areas can become lymphedemic, such as the head, genitals and the trunk of the body.
Lymphedema and edema can cause reduction in mobility, pain, embarrassment and serious emotional depression. Rapid swelling, such as caused by radiation therapy or a surgical operation, can be especially painful as the body tissue is effectively being torn apart by the fluid pressure. The World Health Organization has estimated that approximately 500 million people suffer from some form of lymphedema.
Individual cases of lymphedema are typically diagnosed as belonging to either a primary or a secondary class. Primary lymphedema is a condition where the lymphatic system is chronically or acutely overwhelmed by the volume of lymphatic fluid to be evacuated. Chronic primary lymphedema is often a genetically determined condition. Acute primary lymphedema, and edema, can be caused by an injury or trauma where the lymph system is properly functioning but is temporarily overwhelmed. Swelling and/or edema caused by minor burns, sprains and other injuries are typically alleviated after a few days or weeks in a patient in generally good health. However, even temporary swelling can be painful to the patient and can result in fibrosis (the presence of tough, scar-like tissue).
Secondary lymphedema is typically presents as a relatively sudden cessation or deep reduction of the functionality of a portion of the lymphatic system. The most frequently occurring causes of secondary lymphedema include radiation therapy, mastectomies, amputations and other surgical operations.
Regardless of cause or class, a significant limitation or attenuation of the necessary progress of lymphatic fluid through the lymphatic system may result in a concentration or swelling of the protein bearing lymph fluid in the interstitial area of the soft tissue of an affected limb or body region. Chronic lymphedema more often results in severe and even life threatening consequences than acute edemas.
Any sustained accumulation of proteins delivered to the body tissue by the blood capillaries, and not removed by the lymphatic system, will cause a swelling of fluid in the interstitial areas of the body tissues. The oxygenation of adjacent tissue is then reduced and the healing process is retarded. A localized accumulation of proteins further aggravates this situation by directly stimulating chronic inflammation. Chronic inflammation usually results in the formation and dilation of additional capillaries. These additional blood vessels deliver undesirable excess heat to the swollen area. This undesirable heating of the protein rich interstitial fluid increases the incidence and virulence of opportunistic bacteriological infections.
Conventional treatment techniques for lymphedema include the use of benzo-pyrene drugs, massage therapy, physical exercise, compression bandages and compression garments. Treatment strategies that apply physical pressure to a swollen, edemic or lymphedemic body area can be divided into those which provide intermittent forced compression and those which maintain a relatively constant pressure over time. Looking first at intermittent forced compression devices, Ferrari U.S. Pat. No. 5,025,781 discloses an inflatable cuff that is alternately inflated and deflated to deliver a uniform blanket compression against the circumference of a swollen limb. This action may, however, exacerbate the patient's condition by collapsing blood vessels, increasing leakage into the interstitial areas and obstructing lymphatic outflow.
Bertinin U.S. Pat. No. 5,245,990 describes an inflatable sheath which has tubes that are inflated and deflated in a sequence starting from the most distal and ending at the most proximal. Apparently, Bertinin intends to supply a wave-like massage to the swollen limb. Bertinin's method of timed and sequential inflation and deflation is similar to the invention of Ferrari in that a uniform blanket pressure is exerted against the swollen tissue at any particular moment. This blanket pressure can be ineffective. Furthermore, compressive devices which include pneumatic pumps can cause damage to the health of the patient and must typically by applied by a trained medical practitioner.
Schneider packs can be used to apply constant pressure to a body part. Schneider packs consist of small packs of randomly placed pieces of high density foam bound within a tubular cloth pouch or tube. Schneider packs are incorporated into bandaging and usually cannot be attached by the patient without assistance.
A Reid Sleeve device for treating lymphedema was made by Tony Reid, M.D. and Donald L. Kellogg, one of the applicants of this patent application. The Reid Sleeve device comprises a sheet of convoluted plastic foam and means to push the extending elements or fingers of the convoluted foam sheet against a swollen body part of a patient. The foam fingers are prearranged neatly on the foam sheet in rows and columns and create a grid pattern of high and low pressure areas when pressed against the patient's body area. The convoluted foam sheet is encased in an inner lining of a SPANDEX™ material and an outer lining of relatively heavy nylon fabric. Adjustable VELCRO™-type straps and matching D-ring straps are sewn into the outer lining. The convoluted plastic foam sheet of the Reid Sleeve device is secured and pressed against and/or around a body part of the patient. A medical practitioner can use a pressure gauge while applying the Reid Sleeve device to cinch the VELCRO™-type straps to a particular pressure point or to within a preferred pressure range. The Reid Sleeve device, however, can have disadvantages. The Reid Sleeve arm design is heavy and can weighs over three pounds. Furthermore, the Reid Sleeve device is not configurable to apply pressure to a combination of a limb and an adjacent body area (e.g. leg and groin, leg and hip, arm and shoulder, and etc.) with a single assembly device. The use of the heavy nylon fabric in the Reid Sleeve device, as well as the construction of the Reid Sleeve device, can also limit the adjustability of the Reid Sleeve device to comfortably and appropriately fit different body sizes.
It is, therefore, desirable to provide an improved medical device and process to provide for enhanced medical treatment of lymphedema, edema and other soft tissue swelling.